The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art to the present invention.
Ultracapacitors can be an excellent source of energy in many applications. They offer several advantages over other types of energy storage systems such as batteries. For example, once depleted, ultracapacitors can be recharged at a significantly faster rate than batteries. Under ideal conditions, the recharge rate can be as high as the discharge rate.
Existing recharges for ultracapacitors generally provide a constant current through the ultracapacitor to provide recharging energy. Although this provides a constant recharge rate, the rate is limited by the output current of the recharging energy source. For example, an energy source for recharging may be a 50-volt, 20-ampere, direct current source. The recharging current is limited to the 20-ampere current from the source.
Thus, the time to recharge the ultracapacitor to 100% of capacity is dictated by the output current level of the source. In many circumstances, it would be desirable to achieve a recharge rate greater than that achieved at the current level of the energy source.